Prusa Mini Keeps on Crashing? Here Is Why

Small FDM printers are manufactured by Prusa under the name Prusa Mini+. This is one of the greatest 3D printers you can buy, especially if desk space is a problem for you. It was made with creators in mind, with a focus on quality in design and functionality. Users can anticipate a lesser cost compared to expensive large-scale printers like the MK3 because this printer is smaller than prior generations. Some people, however, have reported that they find their Prusa Minis keep crashing for no apparent reason. But there are plenty of reasons and they vary.

For example, it could be a firmware problem. Or the printer could be experiencing an X or Y-axis crash. This may be because the stepper motor got too hot, layer shifts, lack of lubrication, scraps caught in the belt under the bed, etc.

In this article, we’ll go through each of these reasons in a bit more detail.


Some people complained about randomly experiencing what they call the Blue Screen of Death (BSOD) which caused the printer to stop.

The issue was related to the synchronization of inter-task signals from a message queue, which was sometimes processed erroneously. The web server task, which manages the web user interface, was where the majority of reported BSODs took place. Later, it was discovered that the issue wasn’t the webserver tasks failure; it could have occurred with other services as well, irrespective of whether the printer was connected to the Ethernet (LAN network).

Updates to the most recent firmware version 4.2.1 are advised for a number of firmware versions that may be impacted (4.0.5, 4.1.0, and 4.2.0).

X & Y Axis Crashing

This kind of crash can be caused by a variety of reasons, and it is often accompanied by layer shifts and stringing. Layer shifting is a condition in 3D printing that causes the layers of the printed object to move from where they were supposed to be. It is typically accompanied by aberrant X- and/or Y-axis movement, which causes the extruder head to become misaligned mid-print.

Related: Prusa i3 MK3 Stops Mid Print? Here’s How to Fix

In any case, there is a strong possibility that the crashes will decrease if you work on lowering the layer shifts. You may examine the following reasons for the layer shift or the X/Y crashes:

Hot Stepper Motor

It can be because the stepper motor overheated or because the bearings expand when heated. Open the enclosure door and leave it open, unless you are printing ABS or another high-temperature filament. PETG will overheat at the temperatures you describe, and PLA won’t print accurately at high temperatures. In other words, unless you are printing ABS, open the door.

X/Y Belts

Ensure that belts are securely fastened. When a belt is appropriately tightened, it should produce the sound of a low bass note. If the belts are too loose, tighten them first by undoing the two screws as shown in the illustration below. The two screws at the extreme end of the X-axis should now be tightened. The more tightly they are fastened, the more movement the plastic component has because they are in close contact with the metal rods. To secure the component in place once you’re finished, tighten the first two screws once more.

Ensure that nothing is impeding your axis’s motion. Look for any impediments in the bearings’ route and any potential remnants of past printings that may be attached to the belt (usually around the Y-axis pulley).

X/Y Pulleys

The motor pulley must be properly centred and the belt must be completely straight in order for both pulleys on both axes to be aligned. Ensure that the X-axis belt is not coming into contact with printed items.

X/Y Axis Belt Pulley

The axis may not move completely in sync with the rotation of the motor if the set-screw on the belt pulley has loosened or was not properly fastened to the flat side of the motor shaft.

Due to its location under the bed, the Y-axis set-screw is simple to get, while the X-axis is a little more challenging. Through a hole on the roof of the extruder, users may reach the set-screw for the X-axis. It is a wonderful technique to determine if this is the problem and what has to be disassembled, even if you won’t be able to see if the set screw is properly aligned with the bottom edge of the motor rod, and tightening it will only be a short-term cure.

You must turn the motor in order to see the set-screw if all you can see through the hole is shiny metal. If it is loose, it will budge a little when the motor rotates, exposing the screw.

Related: 3D Printer Filament Keeps Snapping? Here’s What To Do


Crashes also take place when the nozzle strikes an already-cooled filament. The oil on the bed is to blame for the poor adherence. It’s crucial to thoroughly clean your heat bed with hot water, dish soap, and a fresh sponge. Remember to use fresh paper towels to dry it right away. Each printer needs to have lithium grease applied to it after every 800 hours of printing. It makes them operate more effectively and quietly.

Printer Speed

The relevance of this increases while printing larger objects. When printing large objects, it is advised to keep the printer speed at a low setting.

Other reasons

Even after you have lubricated the bearings, the Y axis is sliding just fine, and the belt tension is good, you may still experience problems. If this happens, it may be due to the:

  • Cable bundle hitting the back of a tight enclosure (which can be detected as an obstruction)
  • Slowly failing idler bearing
  • Over tightened Ubolts on the Y axis, or an over-tightened back cover on the X axis

Related: Prusa i3 Belt Tension Guide

Frequently Asked Questions

How Do I Know If Crash Detection Is Turned on in My Prusa Mini?

You may verify that under LCD – Settings – Mode Normal/Stealth and that under LCD – Settings – Crash det., the crash detection is turned on. Pinch the smooth rods in close proximity to the extruder to stop it while printing.

After How Long Does the Prusa Mini Need Maintenance?

The Pura mini printers have an average maintenance interval of about 800 print hours.

What Size Filament Can Prusa Mini Print?

The indirect or Bowden extruder of the Prusa Mini differs from that of the Prusa Original. This 3D printer is not ideal for using flexible filaments because both maintain 1.75 mm filaments.

Final Words

In this article, we discussed reasons for 2 of the most common types of crashes users experienced on their Prusa mini; the firmware crash and the X/Y axis crash. We hope this information will help you diagnose the problem your Prusa mini is facing. Happy printing!

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